Consider the following vectors:

u:<5,8>\displaystyle \vec{{{u}}}:<-{5},{8}>

v:<10,9>\displaystyle \vec{{{v}}}:<-{10},{9}>

y:<15,10>\displaystyle \vec{{{y}}}:<-{15},-{10}>

z:<4,1>\displaystyle \vec{{{z}}}:<{4},-{1}>

u=\displaystyle {\left|{\left|\vec{{u}}\right|}\right|}=